Finally got around to test the Buster RC 1 on my Apollo Lake pc.
Instead of getting stuck with a blinking cursor right after trying to boot from a usb stick, I'm now able to get to the Debian GNU/Linux UEFI installer menu.
However, since my test-device is currently not connected through ethernet, I wasn't able to go any further with the netinst-image. The installer just keeps looking for a CD-ROM drive ("no common CD-ROM drive was detected") that my system doesn't have.
EDIT: Didn't connect the dots and somehow didn't thing about downloading one of the "full" CD or DVD images instead. Downloading one know and will keep you posted how it goes.